lib/src/file.dart - source_span - Git at Google

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 library source_span.file;

 import 'dart:math' as math;
 import 'dart:typed_data';

 import 'package:path/path.dart' as p;

 import 'colors.dart' as colors;
 import 'location.dart';
 import 'span.dart';
 import 'span_mixin.dart';
 import 'span_with_context.dart';
 import 'utils.dart';

 // Constants to determine end-of-lines.
 const int _LF = 10;
 const int _CR = 13;

 /// A class representing a source file.
 ///
 /// This doesn't necessarily have to correspond to a file on disk, just a chunk
 /// of text usually with a URL associated with it.
 class SourceFile {
   /// The URL where the source file is located.
   ///
   /// This may be null, indicating that the URL is unknown or unavailable.
   final Uri url;

   /// An array of offsets for each line beginning in the file.
   ///
   /// Each offset refers to the first character *after* the newline. If the
   /// source file has a trailing newline, the final offset won't actually be in
   /// the file.
   final _lineStarts = <int>[0];

   /// The code points of the characters in the file.
   final Uint32List _decodedChars;

   /// The length of the file in characters.
   int get length => _decodedChars.length;

   /// The number of lines in the file.
   int get lines => _lineStarts.length;

   /// Creates a new source file from [text].
   ///
   /// [url] may be either a [String], a [Uri], or `null`.
   SourceFile(String text, {url})
       : this.decoded(text.runes, url: url);

   /// Creates a new source file from a list of decoded characters.
   ///
   /// [url] may be either a [String], a [Uri], or `null`.
   SourceFile.decoded(Iterable<int> decodedChars, {url})
       : url = url is String ? Uri.parse(url) : url,
         _decodedChars = new Uint32List.fromList(decodedChars.toList()) {
     for (var i = 0; i < _decodedChars.length; i++) {
       var c = _decodedChars[i];
       if (c == _CR) {
         // Return not followed by newline is treated as a newline
         var j = i + 1;
         if (j >= _decodedChars.length || _decodedChars[j] != _LF) c = _LF;
       }
       if (c == _LF) _lineStarts.add(i + 1);
     }
   }

   /// Returns a span in [this] from [start] to [end] (exclusive).
   ///
   /// If [end] isn't passed, it defaults to the end of the file.
   FileSpan span(int start, [int end]) {
     if (end == null) end = length - 1;
     return new FileSpan._(this, start, end);
   }

   /// Returns a location in [this] at [offset].
   FileLocation location(int offset) => new FileLocation._(this, offset);

   /// Gets the 0-based line corresponding to [offset].
   int getLine(int offset) {
     if (offset < 0) {
       throw new RangeError("Offset may not be negative, was $offset.");
     } else if (offset > length) {
       throw new RangeError("Offset $offset must not be greater than the number "
           "of characters in the file, $length.");
     }
     return binarySearch(_lineStarts, (o) => o > offset) - 1;
   }

   /// Gets the 0-based column corresponding to [offset].
   ///
   /// If [line] is passed, it's assumed to be the line containing [offset] and
   /// is used to more efficiently compute the column.
   int getColumn(int offset, {int line}) {
     if (offset < 0) {
       throw new RangeError("Offset may not be negative, was $offset.");
     } else if (offset > length) {
       throw new RangeError("Offset $offset must be not be greater than the "
           "number of characters in the file, $length.");
     }

     if (line == null) {
       line = getLine(offset);
     } else if (line < 0) {
       throw new RangeError("Line may not be negative, was $line.");
     } else if (line >= lines) {
       throw new RangeError("Line $line must be less than the number of "
           "lines in the file, $lines.");
     }

     var lineStart = _lineStarts[line];
     if (lineStart > offset) {
       throw new RangeError("Line $line comes after offset $offset.");
     }

     return offset - lineStart;
   }

   /// Gets the offset for a [line] and [column].
   ///
   /// [column] defaults to 0.
   int getOffset(int line, [int column]) {
     if (column == null) column = 0;

     if (line < 0) {
       throw new RangeError("Line may not be negative, was $line.");
     } else if (line >= lines) {
       throw new RangeError("Line $line must be less than the number of "
           "lines in the file, $lines.");
     } else if (column < 0) {
       throw new RangeError("Column may not be negative, was $column.");
     }

     var result = _lineStarts[line] + column;
     if (result > length ||
         (line + 1 < lines && result >= _lineStarts[line + 1])) {
       throw new RangeError("Line $line doesn't have $column columns.");
     }

     return result;
   }

   /// Returns the text of the file from [start] to [end] (exclusive).
   ///
   /// If [end] isn't passed, it defaults to the end of the file.
   String getText(int start, [int end]) =>
       new String.fromCharCodes(_decodedChars.sublist(start, end));
 }

 /// A [SourceLocation] within a [SourceFile].
 ///
 /// Unlike the base [SourceLocation], [FileLocation] lazily computes its line
 /// and column values based on its offset and the contents of [file].
 ///
 /// A [FileLocation] can be created using [SourceFile.location].
 class FileLocation extends SourceLocation {
   /// The [file] that [this] belongs to.
   final SourceFile file;

   Uri get sourceUrl => file.url;
   int get line => file.getLine(offset);
   int get column => file.getColumn(offset);

   FileLocation._(this.file, int offset)
       : super(offset) {
     if (offset > file.length) {
       throw new RangeError("Offset $offset must not be greater than the number "
           "of characters in the file, ${file.length}.");
     }
   }

   FileSpan pointSpan() => new FileSpan._(file, offset, offset);
 }

 /// A [SourceSpan] within a [SourceFile].
 ///
 /// Unlike the base [SourceSpan], [FileSpan] lazily computes its line and column
 /// values based on its offset and the contents of [file]. [FileSpan.message] is
 /// also able to provide more context then [SourceSpan.message], and
 /// [FileSpan.union] will return a [FileSpan] if possible.
 ///
 /// A [FileSpan] can be created using [SourceFile.span].
 class FileSpan extends SourceSpanMixin implements SourceSpanWithContext {
   /// The [file] that [this] belongs to.
   final SourceFile file;

   /// The offset of the beginning of the span.
   ///
   /// [start] is lazily generated from this to avoid allocating unnecessary
   /// objects.
   final int _start;

   /// The offset of the end of the span.
   ///
   /// [end] is lazily generated from this to avoid allocating unnecessary
   /// objects.
   final int _end;

   Uri get sourceUrl => file.url;
   int get length => _end - _start;
   FileLocation get start => new FileLocation._(file, _start);
   FileLocation get end => new FileLocation._(file, _end);
   String get text => file.getText(_start, _end);

   String get context {
     var line = start.line;
     return file.getText(file.getOffset(line),
         line == file.lines - 1 ? null : file.getOffset(line + 1));
   }

   FileSpan._(this.file, this._start, this._end) {
     if (_end < _start) {
       throw new ArgumentError('End $_end must come after start $_start.');
     } else if (_end > file.length) {
       throw new RangeError("End $_end must not be greater than the number "
           "of characters in the file, ${file.length}.");
     } else if (_start < 0) {
       throw new RangeError("Start may not be negative, was $_start.");
     }
   }

   int compareTo(SourceSpan other) {
     if (other is! FileSpan) return super.compareTo(other);

     FileSpan otherFile = other;
     var result = _start.compareTo(otherFile._start);
     return result == 0 ? _end.compareTo(otherFile._end) : result;
   }

   SourceSpan union(SourceSpan other) {
     if (other is! FileSpan) return super.union(other);

     var span = expand(other);
     var beginSpan = span._start == _start ? this : other;
     var endSpan = span._end == _end ? this : other;

     if (beginSpan._end < endSpan._start) {
       throw new ArgumentError("Spans $this and $other are disjoint.");
     }

     return span;
   }

   bool operator ==(other) {
     if (other is! FileSpan) return super == other;
     return _start == other._start && _end == other._end &&
         sourceUrl == other.sourceUrl;
   }

   int get hashCode => _start.hashCode + 5 * _end.hashCode +
       7 * sourceUrl.hashCode;

   /// Returns a new span that covers both [this] and [other].
   ///
   /// Unlike [union], [other] may be disjoint from [this]. If it is, the text
   /// between the two will be covered by the returned span.
   FileSpan expand(FileSpan other) {
     if (sourceUrl != other.sourceUrl) {
       throw new ArgumentError("Source URLs \"${sourceUrl}\" and "
           " \"${other.sourceUrl}\" don't match.");
     }

     var start = math.min(this._start, other._start);
     var end = math.max(this._end, other._end);
     return new FileSpan._(file, start, end);
   }
 }
	// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	library source_span.file;

	import 'dart:math' as math;
	import 'dart:typed_data';

	import 'package:path/path.dart' as p;

	import 'colors.dart' as colors;
	import 'location.dart';
	import 'span.dart';
	import 'span_mixin.dart';
	import 'span_with_context.dart';
	import 'utils.dart';

	// Constants to determine end-of-lines.
	const int _LF = 10;
	const int _CR = 13;

	/// A class representing a source file.
	///
	/// This doesn't necessarily have to correspond to a file on disk, just a chunk
	/// of text usually with a URL associated with it.
	class SourceFile {
	/// The URL where the source file is located.
	///
	/// This may be null, indicating that the URL is unknown or unavailable.
	final Uri url;

	/// An array of offsets for each line beginning in the file.
	///
	/// Each offset refers to the first character after the newline. If the
	/// source file has a trailing newline, the final offset won't actually be in
	/// the file.
	final _lineStarts = <int>[0];

	/// The code points of the characters in the file.
	final Uint32List _decodedChars;

	/// The length of the file in characters.
	int get length => _decodedChars.length;

	/// The number of lines in the file.
	int get lines => _lineStarts.length;

	/// Creates a new source file from [text].
	///
	/// [url] may be either a [String], a [Uri], or `null`.
	SourceFile(String text, {url})
	: this.decoded(text.runes, url: url);

	/// Creates a new source file from a list of decoded characters.
	///
	/// [url] may be either a [String], a [Uri], or `null`.
	SourceFile.decoded(Iterable<int> decodedChars, {url})
	: url = url is String ? Uri.parse(url) : url,
	_decodedChars = new Uint32List.fromList(decodedChars.toList()) {
	for (var i = 0; i < _decodedChars.length; i++) {
	var c = _decodedChars[i];
	if (c == _CR) {
	// Return not followed by newline is treated as a newline
	var j = i + 1;
	if (j >= _decodedChars.length \|\| _decodedChars[j] != _LF) c = _LF;
	}
	if (c == _LF) _lineStarts.add(i + 1);
	}
	}

	/// Returns a span in [this] from [start] to [end] (exclusive).
	///
	/// If [end] isn't passed, it defaults to the end of the file.
	FileSpan span(int start, [int end]) {
	if (end == null) end = length - 1;
	return new FileSpan._(this, start, end);
	}

	/// Returns a location in [this] at [offset].
	FileLocation location(int offset) => new FileLocation._(this, offset);

	/// Gets the 0-based line corresponding to [offset].
	int getLine(int offset) {
	if (offset < 0) {
	throw new RangeError("Offset may not be negative, was $offset.");
	} else if (offset > length) {
	throw new RangeError("Offset $offset must not be greater than the number "
	"of characters in the file, $length.");
	}
	return binarySearch(_lineStarts, (o) => o > offset) - 1;
	}

	/// Gets the 0-based column corresponding to [offset].
	///
	/// If [line] is passed, it's assumed to be the line containing [offset] and
	/// is used to more efficiently compute the column.
	int getColumn(int offset, {int line}) {
	if (offset < 0) {
	throw new RangeError("Offset may not be negative, was $offset.");
	} else if (offset > length) {
	throw new RangeError("Offset $offset must be not be greater than the "
	"number of characters in the file, $length.");
	}

	if (line == null) {
	line = getLine(offset);
	} else if (line < 0) {
	throw new RangeError("Line may not be negative, was $line.");
	} else if (line >= lines) {
	throw new RangeError("Line $line must be less than the number of "
	"lines in the file, $lines.");
	}

	var lineStart = _lineStarts[line];
	if (lineStart > offset) {
	throw new RangeError("Line $line comes after offset $offset.");
	}

	return offset - lineStart;
	}

	/// Gets the offset for a [line] and [column].
	///
	/// [column] defaults to 0.
	int getOffset(int line, [int column]) {
	if (column == null) column = 0;

	if (line < 0) {
	throw new RangeError("Line may not be negative, was $line.");
	} else if (line >= lines) {
	throw new RangeError("Line $line must be less than the number of "
	"lines in the file, $lines.");
	} else if (column < 0) {
	throw new RangeError("Column may not be negative, was $column.");
	}

	var result = _lineStarts[line] + column;
	if (result > length \|\|
	(line + 1 < lines && result >= _lineStarts[line + 1])) {
	throw new RangeError("Line $line doesn't have $column columns.");
	}

	return result;
	}

	/// Returns the text of the file from [start] to [end] (exclusive).
	///
	/// If [end] isn't passed, it defaults to the end of the file.
	String getText(int start, [int end]) =>
	new String.fromCharCodes(_decodedChars.sublist(start, end));
	}

	/// A [SourceLocation] within a [SourceFile].
	///
	/// Unlike the base [SourceLocation], [FileLocation] lazily computes its line
	/// and column values based on its offset and the contents of [file].
	///
	/// A [FileLocation] can be created using [SourceFile.location].
	class FileLocation extends SourceLocation {
	/// The [file] that [this] belongs to.
	final SourceFile file;

	Uri get sourceUrl => file.url;
	int get line => file.getLine(offset);
	int get column => file.getColumn(offset);

	FileLocation._(this.file, int offset)
	: super(offset) {
	if (offset > file.length) {
	throw new RangeError("Offset $offset must not be greater than the number "
	"of characters in the file, ${file.length}.");
	}
	}

	FileSpan pointSpan() => new FileSpan._(file, offset, offset);
	}

	/// A [SourceSpan] within a [SourceFile].
	///
	/// Unlike the base [SourceSpan], [FileSpan] lazily computes its line and column
	/// values based on its offset and the contents of [file]. [FileSpan.message] is
	/// also able to provide more context then [SourceSpan.message], and
	/// [FileSpan.union] will return a [FileSpan] if possible.
	///
	/// A [FileSpan] can be created using [SourceFile.span].
	class FileSpan extends SourceSpanMixin implements SourceSpanWithContext {
	/// The [file] that [this] belongs to.
	final SourceFile file;

	/// The offset of the beginning of the span.
	///
	/// [start] is lazily generated from this to avoid allocating unnecessary
	/// objects.
	final int _start;

	/// The offset of the end of the span.
	///
	/// [end] is lazily generated from this to avoid allocating unnecessary
	/// objects.
	final int _end;

	Uri get sourceUrl => file.url;
	int get length => _end - _start;
	FileLocation get start => new FileLocation._(file, _start);
	FileLocation get end => new FileLocation._(file, _end);
	String get text => file.getText(_start, _end);

	String get context {
	var line = start.line;
	return file.getText(file.getOffset(line),
	line == file.lines - 1 ? null : file.getOffset(line + 1));
	}

	FileSpan._(this.file, this._start, this._end) {
	if (_end < _start) {
	throw new ArgumentError('End $_end must come after start $_start.');
	} else if (_end > file.length) {
	throw new RangeError("End $_end must not be greater than the number "
	"of characters in the file, ${file.length}.");
	} else if (_start < 0) {
	throw new RangeError("Start may not be negative, was $_start.");
	}
	}

	int compareTo(SourceSpan other) {
	if (other is! FileSpan) return super.compareTo(other);

	FileSpan otherFile = other;
	var result = _start.compareTo(otherFile._start);
	return result == 0 ? _end.compareTo(otherFile._end) : result;
	}

	SourceSpan union(SourceSpan other) {
	if (other is! FileSpan) return super.union(other);

	var span = expand(other);
	var beginSpan = span._start == _start ? this : other;
	var endSpan = span._end == _end ? this : other;

	if (beginSpan._end < endSpan._start) {
	throw new ArgumentError("Spans $this and $other are disjoint.");
	}

	return span;
	}

	bool operator ==(other) {
	if (other is! FileSpan) return super == other;
	return _start == other._start && _end == other._end &&
	sourceUrl == other.sourceUrl;
	}

	int get hashCode => _start.hashCode + 5 * _end.hashCode +
	7 * sourceUrl.hashCode;

	/// Returns a new span that covers both [this] and [other].
	///
	/// Unlike [union], [other] may be disjoint from [this]. If it is, the text
	/// between the two will be covered by the returned span.
	FileSpan expand(FileSpan other) {
	if (sourceUrl != other.sourceUrl) {
	throw new ArgumentError("Source URLs \"${sourceUrl}\" and "
	" \"${other.sourceUrl}\" don't match.");
	}

	var start = math.min(this._start, other._start);
	var end = math.max(this._end, other._end);
	return new FileSpan._(file, start, end);
	}
	}